Source mappings are incorrect if there are braille Unicode characters in source code comments

## Description

When using braille unicode characters (range: `U+2800` to `U+28ff`), the AST source mapping information is incorrect.

## Environment

- Compiler version:
Tried with several `0.8.*` (including latest). I did not try with earlier versions.

I do not know if there are other unicode characters that trigger the bug apart from braille ones.

## Steps to Reproduce

This is a contract containing braille unicode characters:

```solidity

/**
⠴⠁⠀⠚⠀
*/

pragma solidity ^0.8.23;

contract Bad {

uint256 num;

constructor(uint256 _a) {
num = _a;
}
}

```

After compiling it:

```
solc --ast-compact-json Bad.sol
```

We get the following source mapping for the constructor `FunctionDefinition`: `"src": "85:44:0",`.

We can quickly check with JS:

```
const fs = require('fs')

const name = process.argv[2]
const offset = process.argv[3]
const length = process.argv[4]

const source = fs.readFileSync(`${name}.sol`, 'utf-8')
const constructorSource = source.substring(offset, offset + length)

console.log(constructorSource);
```

```
node parse.js Bad 85 44
r(uint256 _a) {
num = _a;
}
}
```

The source is not correct. If we do the same with:

```
/**
Non braille comment
*/

pragma solidity ^0.8.23;

contract Good {

uint256 num;

constructor(uint256 _a) {
num = _a;
}
}
```

After compiling, we get the following source mapping: `"src": "92:44:0",`.

Which is correct:

```
node parse.js Good 92 44
constructor(uint256 _a) {
num = _a;
}
}
```

Start by reproducing the issue with Bad.sol, solc --ast-compact-json, and the parse.js offset check, then compare it with the non-braille example. Trace the compiler's AST source-mapping handling for Unicode characters in comments; done means the constructor mapping begins at the constructor keyword and parse.js prints the complete constructor source.

Written by the indexing model from the issue text.